[Please send plain text.] > But this time ,I traced a bug from user-program to a driver it called: >I inserted the macro (as above ) to driver , but After I made driver xxx.o & >insmod xxx.o , I got (msg as follows) I ain't no kernel hacker but I know that you don't have the usual libraries in kernel mode. Why it even compiled, I don't know. Shouldn't the linker whine about undefined reference as the log functions are in the C lib? >1. Could I use openlog(),syslog(),closelog() in driver ? Just call openlog() once and never mind the closelog. Jonk